Customer Support Center: Knowledge Base

What Is The Difference Between First Stage And Second Stage?

By Bill

(16 ratings)

We recently had a new diver ask about the difference between a first and second stage of a regulator. The short answer is that the first stage is the portion that fits on the tank, while the second stage is the part that you breathe from. The alternate second stage or "octo" is also a second stage, but not the primary one you will always breathe from.